As permanent irritations for the breast may be considered the manifold pressure caused by wearing narrow bodices (corsets). Direct researches on this point have not been made. It is to the point, however, that of 112 cases of von Winiwarter's observations, 61 were affected more in the external, and 15 in the internal portion of the gland, while in 36 cakes the affection began in other places; for we can say that the external por tion of the gland lies more on the corset than does the internal portion. But the fact that, on dividing the gland by a horizontal line passing through the nipple, 52 cases were found to be affected above the line, only 20 below, and 40 cases in other parts, does not accord with this view.
Paget has observed 15 cases in which eczema and psoriasis of the nipple and areola preceded the development of carcinoma by one year. I re member only one single case in which eczema occurred on a carcinomatous breast.
It may also be thought that a permanent intertrigo, which is found under the breasts of fat women, where the skin of the mamma and thorax join, would exert a had influence on the mamma; but Al. von Winiwarter found carcinoma in this situation only twice.
It has also been made a prominent point that carcinoma is especially developed in and from cicatrices and other stabile remains of former in flammations. This opinion is principally due to the observation that cancer of the skin (epithelial cancer, epithelioma) is sometimes formed from fixed, frequently ulcerating scars (especially on the skull and the anterior surface of the tibia). It has never been observed so far as the skin is concerned, that a mammary or epithelial cancer has arisen from a cicatrix of the mamma. As regards the observations according to which carcinomas of the mamma have developed from cicatrices in the interior of the mamma this would not be proved, simply because it is repeatedly stated in reports that an abscess had developed in former years after confinement in the same mamma in which a carcinoma was found at the time of exami nation, because it is difficult to establish the proof that the carcinoma was developed from the scar in the interior of the mamma. Another con nection between mastitis and carcinoma is imagined from the statements of the affected women, that after the cessation of a puerperal mastitis, a nodule remained in the affected breast from which a carcinoma developed after several years. Al. von Winiwarter has sufficiently proved and shown, regarding his 9 cases, that there were 44, 5, 7, 10, 16, 20, 21, 25, and 28 years between the mastitis and the development of carcinoma. Finally
it should also be considered that probably quite often a few not dilated lacteal lobules are broken off from their connection with their excretory ducts by suppurative mastitis, and that such lobules may be brought into functional activity by a subsequent pregnancy; the secretion then formed must be either totally or partially absorbed, and in the latter case it would probably remain inspissated. From this it should be expected that milk and butter cysts must often be developed after mastitis, but such is not the case. There is still the hypothesis that in such occluded gland lobules the epithelium is especially disposed to atypical proliferation, and that carcinomas are thus originated. It would be very difficult to prove this hypothesis; and statistics indicate otherwise. Al. von Wini warter found that of 114 women affected with mammary carcinoma, 24 (21.05 per cent.) had had mastitis. If now mastitis is very frequent and carcinoma likewise very frequent, so that a coincidence of the two pro cesses will not be surprising, the frequency of mastitis to all cases of con finement, according to Winekle's statistics, is still only 6 per cent. If then there be no especial contingencies in Al. von Winiwarter's statistics, we may assume provisionally that women who have had mastitis are more disposed to carcinoma than those who have not had it. As regards the nodules which commonly remain in the breast after confinement, I must say that those which I have had occasion to examine (I do not mean that I have extirpated and anatomically examined such nodules) seemed very much like small nodular adeno•bromas. It is very possible that they may have existed before confinement, though not detected in the firmer mamma; they had perhaps enlarged during pregnancy and lactation, and were therefore more noticeable when the gland became more relaxed.
So far as we may go in our search for further, newer irritation, which may possibly cause the origin of tumors, the objection always remains that in this way, probably, various acute and chronic inflammatory pro cesses, and perhaps also the formation of retention-cysts and the like, may be explained, but not the formation of peculiar pseudo-plasms. We are thus always drawn into the territory of hypotheses, whose foundations derived from observation belong to the class inexplicable, even if they are not wholly without reason.